Quantitation of volatile PFAS in environmental samples using SPME Arrow and Orbitrap Exploris GC

Importance of the Topic

Per‐ and polyfluoroalkyl substances (PFAS) are a class of persistent chemicals widely used in industrial and consumer products. Volatile PFAS, including fluorotelomer alcohols (FTOHs) and related derivatives, can be released into the environment during manufacturing and usage. Monitoring these neutral PFAS species is critical because they can travel through air and water, accumulate in ecosystems, and pose potential health risks. Developing sensitive, robust analytical workflows for volatile PFAS in complex environmental samples addresses stringent regulatory requirements and emerging concerns over less‐studied PFAS compounds.

Objectives and Study Overview

This study aimed to demonstrate a streamlined method for simultaneous quantitation of volatile PFAS in environmental matrices. Using solid‐phase microextraction (SPME) Arrow coupled to high‐resolution, accurate‐mass (HRAM) Orbitrap Exploris GC mass spectrometry, the approach was evaluated for:

• Sensitivity and selectivity at low ng/L levels.
• Minimal sample preparation to reduce handling and contamination.
• Capability to perform retrospective screening of additional compounds via full‐scan acquisition.

Methodology

Water samples (river water, groundwater, landfill leachate, trade effluent, sewage) were spiked with PFAS standards and internal isotope‐labeled analogues. A 10 mL aliquot, internal standard mix, and methanol were placed into a 20 mL headspace vial. Incubation at 70 °C for 5 min with agitation preceded an 8 min SPME Arrow extraction. The fiber was thermally desorbed in splitless mode via a GC injection port. Calibration curves (5–125 ng/L) assessed linearity, while replicate analyses at 1 ng/L defined limits of detection (LODs) and quantification (LOQs). Recoveries were determined at 25 and 125 ng/L spikes in river water.

Instrumentation Used

• Autosampler: Thermo Scientific TriPlus RSH SMART with SPME Arrow.
• GC System: Thermo Scientific TRACE 1610 GC with TraceGOLD TG-5SilMS column (30 m × 0.25 mm × 0.25 µm).
• Mass Spectrometer: Thermo Scientific Orbitrap Exploris GC in full‐scan EI mode (50–750 m/z) at 30,000 resolving power.
• Data Processing: Chromeleon 7.3.2 for targeted quantitation; Compound Discoverer with HRAM Contaminants Library for screening.

Main Results and Discussion

Target PFAS compounds (FTOHs, FTACs, FTMACs, FTIs, Me/Et-FOSAs, Me/Et-FOSEs) exhibited linear calibration (R2 > 0.99). LODs ranged from 0.1 to 1.4 ng/L; LOQs from 0.35 to 4.5 ng/L. Recoveries in river water spiked at 25 and 125 ng/L were 76–115% with relative standard deviations generally below 15%. Real sample analysis revealed PFAS in all matrices; crude sewage contained up to 1,050 ng/L of 6:2 FTOH, while landfill leachate and effluents showed multiple PFAS at ng/L–hundreds of ng/L levels. Full‐scan data enabled detection of additional contaminants, such as dichlorobenzene in landfill leachate, via spectral library matching with sub‐ppm mass accuracy.

Benefits and Practical Applications

• Automated SPME Arrow reduces manual handling and contamination risk.
• High resolution full‐scan Orbitrap GC‐MS allows simultaneous targeted quantitation and non‐target screening.
• Robust performance in diverse environmental matrices supports regulatory compliance at low reporting limits.

Future Trends and Potential Applications

Advances may include expanded spectral libraries for non‐target PFAS, development of isotope‐labeled standards for all PFAS classes to improve precision, and adaptation of SPME Arrow methods for air sampling. Integration with data‐mining algorithms will further enable comprehensive environmental surveillance of emerging PFAS and related contaminants.

Conclusion

The combination of SPME Arrow and Orbitrap Exploris GC provides a sensitive, robust workflow for volatile PFAS analysis in complex environmental samples. Full‐scan HRAM acquisition extends the method beyond the target list, enabling rapid screening and retrospective data analysis. The approach meets stringent sensitivity requirements and improves laboratory throughput, addressing growing analytical demands for volatile PFAS monitoring.

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